Rotary pulp-screen.



R. S. CLARKE.-

ROTARY PULP SCREEN. APPLICATION FILED JULY 6, 1914.

1,131,599. Patented Mar.9, 1915.

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v ROTARY P ULP SCREEN. APPLICATION FILED JULY 6, 1914.

1,131,599? Patented Mar.9,1915.

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TATE f ATENT RALPH S. CLARKE, 0F WALPOLE, MASSACHUSETTS, ASSIGNOR TOWANDEL SCREEN MANUFACTUBING CQMPANY, A CORPORATION OF MASSACHUSETTS.

ROTARY PULP-SCREEN.

Specification of Letters Patent.

Patented Mar. $1), 1935..

Application filedfiuly 6, 1914. Serial No. 849,160.

To all whom it may concern:

Be it known that I, RALPH S. CLARKE, a citizen of the United States,residing at Walpole, in the county of Norfolk and State This inventionhas reference to improvements in rotary pulp screens in which the rotaryscreen is caused to oscillate to assist the operation of screening thepulp and to intermittently rotate to progressively carry the pulpgathered by said screen to a position to be acted upon by the waterspray.

One object of the invention is to so construct a rotary pulp screen thatthe screen may be caused to oscillate to assist the screening of thepulp without the use of buffers to yieldingly resist the reaction of thescreen, and to avoid the undue chattering caused by the reaction of thepulp screen with the resultant undue wear on the machine. 7

Another object of the invention is to so construct a rotary pulp screenthat intermittent rotation of the screen may be effected by frictionalengaging means whereby the expense and the wear of the usual worm geardriving means is eliminated.

Other objects of the invention will appear from the followingdescription.

lhe invention consists in the novel means for effecting the vibration oroscillation of the screen carrying member or frame so that the reboundblow of said member or frame is dispensed with and that the wear of theparts by which the oscillation or vibration ofsaid frame or member issuch that undue oscillation of the screen and consequent racking actionon the machine as a whole is avoided.

The invention also consists in the means for frictionally driving thepulp screen to effect its intermittent rotation.

The invention also consists in such other novel features of constructionand combination of parts as shall hereinafter be more fully describedand pointed out in the claims.

' Figure 1, represents an end elevation of a rotary pulp screenillustrating the new invention. Fig. 2, represents a side view ofportions of the same. Fig. 3 represents an end View of the machineillustrating a modified construction of the friction driving device.

Similar characters of reference designate corresponding partsthroughout.

As heretofore constructed rotary pulp screens of this nature have beensupplied with frames or members pivotally mounted and having projectingor striking members adapted to be acted upon by rotary ratchets toeffect themovement, in one direction, of said pivoted members and thescreens carried thereby to assist the screening of the pulp taken up bysaid screens. The reaction or rebound of said pivoted members has beenlimited by the use of buffers with the view that after each reaction ofsaid pivoted members said striking members would be positioned to beacted upon by the next succeeding tooth of the ratchet and moved therebyalways the'same distance. In practice it is found that the buffers soonbecome worn and permit the movement of the striking members beyond thepredeterminedpoint at which the teeth of the ratchet should act thereon,after such wearing of the buffers, the teeth of the ratchet would strikesuch striker members with constantly increasing force thus causing unduemovement of said pivoted members and also a racking or shaking of thewhole machine.

In such machines, as heretofore con structed, the means for effectingthe rotation of the pulp screen comprised an annular worm gear driven bya worm which driving means was expensive in construction and,.largely onaccount of the oscillation of the screen and its gear relative to theworm, would soon become worn and, ultimately, useless.

In carrying this invention into practice it hasbe'en, my object tosimplify the construction of rotary pulp screens as to their irivingmeans by eliminating the usual bufprs and the usual worm and worm geardrive and thereby reduce the original cost of the machine and to prolongits life. I

have also had in mind the avoidance of con siderable of the noise causedby the con tinual striking of the ratchet against the striker member ormembers.

In the drawings 1 have shown this invention as applied to a machinehaving but one pulp pan and a single screen but it is obvious that thenew improvement may be applied,

by mere duplication of parts to a machine having two pulp screens of thegeneral nature of that herein shown.

' As shown in the drawings in its preferred form the pulp pan 5 issustained by the usual end frames 6, 6 which constitute part of anysuitable base or support for the machine. On said frames 6, 6 at oneside of the machine is mounted a pair of brackets as 7, and at the otherside of the machine is mounted a pair of brackets 8, 8. In these latterbrackets 8, 8 is journaled the drive shaft 9 adapted to be driven in anyordinary manner and having the eccentric disks 10,10 and the cams 11, 11which latter have peripheries defining a succession of regular rises andfalls of comparatively sharp pitch. Pivot ally sustained by pivots ofthe brackets as 7 are the screen sustaining arms 12, 12 having at theirfree ends the slidably adjustable blocks 13, 13 having the followermembers 14, 14 shaped to follow the peripheries of their related cams11, 11.

Journaled in bearings of the arms 12, 12 is the pulp screen 15 havingthe cylindrical extensions 16, 16 on which are clamped the split collarsas 17 of the friction drums 18, 18. Mounted on the-eccentric disks 10,10 are the straps or frames 19, 19, in which said disks are free torotate, and having the arms 20, 20 to which are attached the frictionstraps or belts 21, 21 which latter extend partially around theperipheries of the drums 18, 18 and then over the pulleys as 22rotatable on studs extending from the arms 12, 12, and said belts 21, 21are held under tension in frictional contact with the drums 18, 18 bytheir weights 23, 23.

The operation of the device, thus de scribed, is as follows. When shaft9 is rotated its cams 11, 11 will act on the followers 14, 14 to eifectthe rise and fall of the free ends of the arms 12, 12. While therelative shape of these cams and their follower is such that the riseand fall ofthe followers 14, 14-may be regular the irregular action toeffect chattering of the pulp screen to loosen the pulp thereon may beeffected by the number of rises on the peripheries of said'cams 11, 11or by the speed at which shaft 9 is driven but, in actual practice, itis found that with the followers 14, 14 in practically constant contactwith the peripheries of cams 11, 11 the shaking action efiected on" thescreen is sufiicient. Attention is called to the fact that the wear ofthe followers 14, 14, on their cams 11, 11 will be regular and that anyreaction of said followers will be directly on the face of the cams.During such rotation of shaft 9 eccentric disks 10, 10 operate to effectreciprocating movement of their arms 20, 20 with the result that at eachforward movement, toward belt 21, of said arms 20, 20 said belts areslackened and the weights as 23 are permitted to take up the dricalfriction drum,

menses slack of. such belts, while on the retractive effectingintermittent rotation of the screen.

This modification consists in providing a part of the machine which isfixed relatively to the vibration of arms 12 with the pin 24 from whichthe frictionbelt 25 extends over the drum 18 and is furnished at itsfree end with the tension weight '26. In this modified form when thescreen 15 is raised by the actions of the cams 11 on their followers 14,14 the frictional contact of the belts as 25 on the drums 18 will eflectthe drawing around of said drums in the direction indicated by the arrowof said screen, and the weights as 26 will rise. 0n the' downwardmovement of the screen said weights as 26 will take up the slack of thebelts as 25.

While I have herein shown a specific con struction of my improved pulpscreen it is not my intention to limit my invention except as hereinclaimed.

Having thus described my invention 1 claim as new and desire to secureby Letters Patent- 1. A rotary pulp screen having a cylinand a frictionbelt partially embracing said drum and having a slack take up, incombination with means for effecting relative movement between said drumand said belt whereby the frictional engagement between said belt andsaid drum causes intermittent rotation of said drum in one direction.

2. A rotary pulp screen having a friction drum, and a friction beltpartially embracing said drum and having a slack take up, in combinationwith means for moving said screen and its drum intermittently verticallya limited degree against the frictional resistance of said belt on saiddrum.

3. A cylindrical pulp screen rotatably mounted and having a frictiondrum, and a friction belt partially embracing said drum and having aslack take up, in combination with a frame, a pivoted arm carried bysaid frame, and means for efiecting vibration of said arm.

4. A pulp screen comprising a frame, arms mounted on said frame toswing, means for vibrating said arms, and a cylindrical pulp screenrotatably mounted on said arms and havinga friction drum, in combinationwith a friction belt mounted in the machine and in contact with saiddrum and having a free end provided with a weight.

5. A pulp screen comprising a frame,

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arms mounted on said frame to swing a rotatable cylindrical pulp screencarried by said arms and having a friction drum, in combination with arotatable shaft havingcams for effecting vibration of said arms, a beltin frictional contact with said drum, and means carried by said shaftfor intermittently actuating said belt in one direction. v

6. A pulp screen comprising a frame having a pair of pivoted arms,followers adjustably mounted at the freeends of said arms, a cylindricalpulp screen rotatably carried by said arms and having a friction drum, arotatable shaft extending approximately parallel to said screen andhaving cams cooperating with said followers, an eccentric on said shaft,a bearing frame on said eccentric, and a friction belt attached to saidbearing frame and partially embracing said drum, said belt having aslack tak-

